The objectives of this study are to synthesize five series of 1-arylcarbamoyl-1, 2-diazacycloalkanes and determine their anticonvulsant activity and neurotoxicity. The pharmacological testing will be carried out by the Antiepileptic Drug Development (ADD) Program of NIH. The proposed compounds are analogs of 1-methyl-2-(2',6' -dimethyl-phenylcarbamoyl)pyrazolidine (17053) which has been selected for Screen 3 Testing by the ADD Program. Synthetic objectives include: a) variation of the alkyl group at N-1; b) variation of the size of the heterocyclic ring including 4,5,6 and 7 members; c) introduction of alkyl and aryl substituents at various carbons of the heterocyclic ring; d) introduction of various substituents into the phenylcarbamoyl aromatic ring and e) preparation of compounds containing heterobicyclic rings. This project necessitates the synthesis of numerous 1,2-diazacycloalkanes which will be adducted to various aryl isocyanates to give the title compounds.